Imagine being able to organize and structure your Arquillian tests as human-readable specifications by example that describe at a high-level how the application should work, then being able to present illustrated documentation generated from a test run that gives all parties an account of the features under development and tracks feature sign-off through automation of the acceptance criteria.

This goal can be achieved by Thucydides and Arquillian joining forces. Acceptance tests will not only be agile and illustrated, but fully automated. With a proof of concept in hand, we plan to advance this combination, including substituting Arquillian Drone to manage WebDriver, at the Devoxx 2012 Hackergarten.

Introducing the candidates

What is Thucydides?

Thucydides is a testing tool that encourages developers write more flexible and reusable end-to-end acceptance tests. In the style of Acceptance Test-Driven Development, Thucydides introduces a narrative for tests that describes the high-level requirements and automates the acceptance criteria using the tests. Developers then iterate using a test-driven approach to complete the requirements (i.e., stories), as depicted in the diagram below.

By analyzing the test metadata and test results, Thucydides generates illustrated documentation that describes how the application is used in the form of high-level requirements, acceptance criteria and screenshots, and records the progress of development.

What is Arquillian?

Arquillian is open source software that empowers you to test JVM-based applications more effectively. Created to defend the software galaxy from bugs, Arquillian brings your test to the runtime so you can focus on testing your application’s behavior rather than managing the runtime. Using Arquillian, you can develop a comprehensive suite of tests from the convenience of your IDE and run them in any IDE, build tool or continuous integration environment.

What is Arquillian Drone?

Arquillian Drone is an extension to Arquillian that manages the lifecycle of browsers for the purpose of controlling them from a test, thus simplifying automated functional / acceptance testing. Drone bootstraps the tooling necessary to send commands to the browser (e.g. Selenium Server, WebDriver, etc), spawns an instance of a browser, injects the browser API into the test class to allow tests to control that instance and, finally, properly disposes of the browser instance after the test is complete.

Integration benefits

Arquillian and Thucydides as yin and yang

While Thucydides handles automation of the browser—via the WebDriver library—it does not handle deploying the application being tested, nor does it manage the lifecycle of the container to which the application is deployed. In other words, it doesn’t automate everything. That’s where Arquillian steps in.

Thucydides brings the ATDD methodology and rich test reports to Arquillian, both new features to the Arquillian ecosystem. Arquillian complements Thucydides by managing the lifecycle of the container and deploying the application (as a whole or micro-deployment) to it. These services would otherwise need to be handled by the build when using Thucydides alone.

Beyond their combined core feature set, the integration brings all of the Arquillian extensions to Thucydides tests, opening the door to services such as loading seed data into the database, measuring performance and even managing browser automation. Speaking of managing browser automation…

More powerful browser automation with Drone

Bringing Arquillian Drone into the fold provides additional benefit by introducing a more powerful and flexible choice for controlling the browser in a Thucydides test, including simplified configuration, alternatives to WebDriver and extensions (e.g., Graphene). This secondary integration between Arquillian and Thucydides also unifies the developer experience with regard to how the browser is controlled across vanilla Arquillian Drone tests and Thucydides tests (embracing the concept that each tool should focus on doing one thing well).

Basic integration between Arquillian and Thucydides is a first step and getting Drone integrated is an optional (but valuable) bonus.

Use Graphene page fragments to reduce boilerplate code common in acceptance tests*

* requires Drone integration

Balancing responsibility

Thucydides’ strong suit is promoting ATDD through its programming model for writing acceptance tests as specifications by example and its reporting pipeline that summarizes test results as user stories. We believe Thucydides could move faster by focusing on tools and metrics needed to facilitate ATDD, allowing Arquillian to address the need of general purpose test extensions such as alternate test runners, data loading, browser automation, programming model integration, etc. In other words, Thucydides has more freedom to focus on its core competency, as stated on its website:

Organize and structure acceptance tests, associate tests with the user stories or features that they test and generate illustrated documentation describing how the application is used based on the stories described by the tests.

Hacking on the integration

We plan to hack on this idea during the Hackergarten at Devoxx 2012. Keep in mind there is a proof of concept we can reference as a starting point, described later in this section.

John Smart, the author of Thucydides, has offered to host the integration in the Thucydides code base, which is fantastic.

When and where are we hacking?

We are going to use the free Hackergarten day at Devoxx 2012 as an opportunity to put our heads together to make progress on this integration. Here are the details:

We’ll also be hacking throughout the week, either at the long white “hacking” tables on the second floor of the venue or after hours at a bar. Of course, anyone is welcome to hack on this idea at anytime from anywhere. This is open source!

Karel Piwko (Arquillian Drone Lead) and Vineet Reynolds (Arquillian Core and Thucydides integration) will be participating, time permitting, from afar. Feel free to reach out to them on IRC or the forums.

What we want to achieve

The following two tests are proposed milestones we want to achieve during the hack. They contrast what integration looks like without Drone to the integration with Drone. Thinking through these scenarios helps reveal integartion points that need to be exposed or refined.

The tests in this section apply to the Beer Advisor sample application.

Sample code to use for exploring the integration

Prior work

Vineet Reynolds has been experimenting with an integration between Thucydides and Arquillian Core. Vineet’s integration code uses a Thucydides StepListener implementation to weave the Arquillian lifecycle into the test. Tests are run using the Thucydides testrunner, while Arquillian manages the container lifecycle and performs the deployment of archives defined in the tests. The integration does not incorporate Arquillian Drone, opting to leave management of WebDriver up to Thucydides.

Aslak and Bartosz improved upon the integration and incorporated it into the Beer Advisor sample app for their JavaZone talk in September 2012. They introduced a JUnit Rule that activates the Arquillian services that run before and after each test method, such as test enrichment. A JUnit Rule is currently necessary due to insufficient hooks in Thucydides, but it gets the job done. Eventually we want to phase out the JUnit Rule because it exposes integration plumbing in the test.

Engineering challenges

Challenge #1: Unified test runner

Thucydides needs a startup API that isn’t coupled with JUnit so that Arquillian is able to perform the startup in an extension. At the moment there is a lot of setup code in the ThucydidesRunner to reproduce. The alternative is that Thucydides provides enough hooks in its StepEventBus for Arquillian to hook its own startup into the Thucydides lifecycle. In the integration prototype, a JUnit rule is used to activate Arquillian in a Thucydides test, but this is not the most elegant approach.

Ideally, the @RunWith(Arquillian.class) annotation should be enough for Arquillian to drive Thucydides if Arquillian detects Thucydides is also in use (e.g., the @Story annotation is present on the test class). This is the preferred approach since it simplifies the experience for the user across the test suite (a single @RunWith for all integration tests) and it may make the integration more compatible with extensions since Arquillian has a more sophisticated event bus.

Challenge #2: Drone integration

When Drone is integrated, the user has an option to use the browser automation library (directly or via the page object pattern) as with other Drone tests or use the page object support provided by Thucydides. Drone should be able to pass Thucydides the WebDriver instance so that Thucydides can operate its own page objects.

Ideally, the integration with Drone should cut down on as many redundant declarations in the class as possible to simplify test authoring. That means that the @Drone injection point is used to access the browser instance and and @ArquillianResource URL injection point is used to access the initial (base) url.

Karel Piwko mentioned that Drone needs a better SPI for improved integration with Arquillian Graphene, slated for 1.2.0.Final. He believes the Drone SPI will also help facilitate Thucydides integration. It also opens the door for Drone to be integrated into Thucydides on its own.